Identifier: textbookonelectr03inte (find matches)
Title: A textbook on electric lighting and railways. International correspondence schools, Scranton, Pa. v. 1-3, 5
Year: 1901 (1900s)
Authors: International Correspondence Schools
Subjects: Electric engineering Electric lighting Electric railroads
Publisher: Scranton, International Textbook co.
Contributing Library: Northeastern University, Snell Library
Digitizing Sponsor: Northeastern University, Snell Library

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e the drawing; for example, connec-tions are not shown for the switchboard or instrumentlamps or for the exciting circuit of the Thomson ammeters;if Weston instruments were used, these latter connectionsAvould not be required. Only two feeder panels are shown,as the connections for all of them are alike. In thisdiagram the equalizer switch E is shown mounted on astand near its machine, as this is the practice followed inthe more recent plants. The -f- and — leads from the gen-erators lead directly to the lower posts of the main switches.The upper posts of the + switches connect directly tothe -(- bus-bar A. The upper posts of the — switches con-nect, through the ammeter shunt B and circuit-breaker C,to the — or rail bus-bar /A Note that the ammeter andcircuit-breaker are not connected in the -j- side. This isbecause the equalizer is connected to the -;- side and themachine might be sending current through the equalizer, inwhich case the current in the -;- side on the switchboard
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§•21 ELECTRTC^ RATLAVAYS. 11 would not \)c the total cnrrcnt delivered ))y the machine.Under such circumstances, an ammeter connected in the+ side would not give true indications. Of course, tlieeqtializer Avill work all right no matter whether the pole itis connected to is -;- or —, the only condition being that itmust connect together the points where the I)rushes areconnected to the series winding. The + bus-bar A A i^ carried through the wattmeter asindicated at 11, so that the whole current passes through11 on its way to the feeder panels. The shunt F for thetotal-output ammeter 10 is also connected in series with Abetween the generator and feeder panels, so that 10 indi-cates the total current. The voltmeter is connected to either machine by means ofthe plug receptacles a, /;, c, (/; a and d are in each caseconnected to their respective dynamo terminals, while c and dare connected to the voltmeter. When the plug is inserted,a is connected to c and /; to (/, thus giving a re

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